Electron microscopic observation of uniform macroporous particles. II. Effect of DVB concentration

摘要

The electron microscopic observation of uniform and macroporous poly(styrene-co-divinylbenzene) particles prepared by a two-step seeded polymerization method was performed. In the synthesis of uniform macroporous particles, the uniform polystyrene latices produced by a dispersion polymerization method with two different sizes and average molecular weights were utilized as the seed particles. The seed particles were first swollen with dibutylphthalate and then with a monomer phase, including styrene and divinylbenzene. The macroporous structure of the final particles was achieved by using a porogen mixture consisting of dibutylphthalate and linear polystyrene. The linear polystyrene part of the porogen solution was directly obtained from the seed latex. The macroporous particles with different diameters and porosities were produced by changing the divinylbenzene concentration between 25 and 100% in the repolymerization step. The effect of divinylbenzene concentration on the size and the surface morphology of the final particles were investigated by scanning electron microscopy. The internal structure of the final particles was analyzed by transmission electron microscopy. The results indicated that the average size of the final particles increased with the increasing divinylbenzene concentration. The increase in the DVB concentration also led to an increase in the average pore size.